It has also been identified as granular black masses associated with stibnite, schafarzikite and metastibnite, and rarely as prismatic crystals to 2 cm in the quartz-stibnite-antimony veins.
In the course of identifying the myriad red powdery minerals observed on fracture surfaces at Lac Nicolet, the rare mineral schafarzikite was identified by X-ray diffraction, and confirmed by semiquantitative EDS microprobe analysis.
Metastibnite, schafarzikite, stibiconite and very minor senarmontite appear late in the paragenetic sequence, and may be either very late hypogene or supergene minerals.